Metals influencing migration

Particular features of metal packaging influencing migration... 

Catalysts have a profound effect on the extent of double-bond migration. The influence is a property of the metal itself and its structure and is little altered by the support(7 7,7 ). It is related to the relative tendencies of the half-hydrogenated states to reform an unadsorbed olefin. A decreasing ordering of metals for double-bond migration (46) is Pd > Ni Rh Ru Os > Ir - Pt. 

This perturbation is then propagated via the spatial constancy of the Fermi level Ef throughout the metal film to the metal-gas interface G, altering its electronic properties thus causing ion migration and thus influencing catalysis, i.e. catalytic reactions taking place on the metal-gas interface G. 

Heavy metals in the environment, especially their accumulation in soils, is a serious environmental problem which the whole world faces (Du et al. 2005). The farmland soils are an important media of the ecological cycle of Cadmium, and its harm to human health can t be neglected (Wu et al. 2004). Heavy metal migration, transformation and toxicity to plants in soil are directly influenced by the quantity proportions of various forms (Zhu et al. 2002). The toxicity of water-extractable and adsorbed and exchangeable metals are the greatest, and residual metals is the lowest (Liu etal. 2002). Different forms have different bioavailability thus their influences on the environment and human health are different. It is critical to have a good understanding of Cadmium forms in soil. This paper describes the Cadmium forms in the acid soils of eastern China. 

The amount of organic matters not only determines the nutrition of the soils, but also form complex compound with heavy metals to influence metal migration and bioavailability (Liu et al. 2002). From table 1, we can found that extractable Cd contents, especially occluded Cd onto Fe-Mn oxides and organically bounded Cd has a prominent positive correlation with organic matters (a =0.05,n =30, F =0.361), (Fig. 2). Organic matters are one of the major factors which influence Cd... 

Acid Deposition Influence on the Biogeochemical Migration of Heavy Metals in Food Webs... 

ESR and ESEM studies of Cu(II) in a series of alkali metal ion-exchanged Tl-X zeolites were able to demonstrate the influence of mixed co-cations on the coordination and location of Cu(II) (60). The presence of Tl(l) forces of Cu(II) into the -cage to form a hexaaqua species, whereas Na and K result in the formation of triaqua or monoaqua species. In NaTl-X zeolite, both species are present with the same intensity, indicating that both cations can influence the location and coordination geometry of Cu(II). The Cu(II) species observed after dehydration of Tl-rich NaTl-X and KT1-X zeolites was able to interact with ethanol and DMSO adsorbates but no such interaction was observed with CsTl-X zeolites. This interaction with polar adsorbates was interpreted in terms of migrations of the copper from the -cages. 

In the case of cytochrome c, these electrostatic terms are due to changes in the redox states of the internally bound protein metal ion. In other cases where the charges on anions or cations are numerically fixed, the ions can dissociate (e.g., as the metal ion leaves the protein) or migrate (e.g., Na% K+, Ca2+, Cl-, HPO2, H+). If the exchange of these ions involves sites, especially hydrophobic sites, deep inside proteins, on the one hand, and free solution or surface sites, on the other hand, then they will be expected to have an electrostatic influence on the protein much as in a change of redox state. Thus we look next at two calcium binding proteins and later at insulin. 

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